PIV through moving shocks with refracting curvature

Particle image velocimetry (PIV) is applied to moving millimeter shock waves whose density jump and small radii of curvature make refraction significant. The motion of the shock front is also much larger than the motion of the corresponding mass at the front. A Lagrangian model of particle displacement in response to a moving shock is developed to investigate the relationship between particle displacements and the actual mass velocity behind the shock. Errors in PIV measurements due to light refraction across a curved, moving shock are investigated in terms of both position and velocity errors using a refraction model developed from geometrical optics. The model is experimentally validated and applied to 1-D slices of data extracted from PIV vector fields, and the resulting measurement errors are quantified.